Double lift single screw jack



Sept. 25, 1934. J MORRISON 1,974,687

DOUBLE LIFT SINGLE SCREW JACK Filed July 28, 1953 Patented Sept. 25, 1934 PATENT; OFFICE UNITED STATES 1,974,687 i DOUBLE LIFT SINGLE somsw JACK er John A.'Morrison, Warren, Ohio Application July28, 1933, Serial 'No.682,561

6 Claims. (oi. ash-103 The invention relates to lifting jacks espe- ;cially adapted for raising automobiles, trucks and other vehicles and more particularly to a double lift jack operated by a single screw.

"Jacks of this particular type comprise two hollow or tubular lifting members adapted to be ropera ted by a single screw, one lifting member being raised; by means ofthe screw, to a predetermined height at which point it is automatically locked to the other lifting member and disengagedfrom the screw while the second lifting member is automatically brought into engagement with the screw and raised thereby, carrying with it the first lifting member locked thereto in extended position.

The object ofthe present improvement is to fpjfovide asimple, inexpensive and efficient lifting erate'dby a single screw. v

A further object is to provide 'a lifting jack of this character whichdoes not require the use -of any extra locking means, one of the lifting fmembers being automatically locked directly to the other lifting member at a predetermined position during the operation of the jack. Another object is to provide a jack of this character comprising two telescoping tubular "lifting members with means forpreventing turning. of one member and-means for causing the other member to turn at a predetermined time to lock the two members together when the inner 'member has reached, the limitof its movement jack having two lifting members successively oprelative to the outer member, t A still further object 'of the improvement is to 7 -provide such a lifting jack in which the outer itubular lifting member is provided with one or more openings near its upper end and the inner ilifting member is provided with oneor more lugs or projections near its-lower end, adapted to be automatically engagedin said openings when the inner memberhas reached a predetermined height, wherebythe inner and. outer 'members are directly locked to each other. 1 i i i.

The above objects, together with others which wili be readily apparent from thefollowing deseription and :the accompanying drawing, or -which may be later pointed out, may be attained by constructing the improved lifting jack 1 5 in the manner illustrated in the drawing, .in

which Figure 1 is a vertical sectional view of the .improved jack showing the same in the lowered or, collapsed position, taken as on the line 1-1,

base "13.

Fig. 2, a top plan view with the lifting cap removed;

Fig. 3, a vertical sectional view of the upper portion of the housing of the jack;

Fig. 4, a sectional elevation of the upper portion of the housing showing the outer tubular lifting member and the lower portion of the inner lifting member in the raised or extended position; 7 f,

Fig. 5, a transverse section through the housing taken as on the line 5--5, Fig. 3;

Fig. 6, a transverse sectional view through the locking portions of the inner and outer lifting members in locked position, taken as on the line 6-6, Fig. 4; t

Fig; 7, a detail perspective View of the lower portion of the inner liftingmember; and

Fig. 8, a similar view of the upper portion of the outer lifting member.

Similar numerals refer to similar parts 7 5 throughout the drawing.

which meshes therewith.

The pinion 16 is fixed upon the inner end of a short shaft 17 journaled in the bearing 18 preferably formed integral with the enlarged portion 11 of the housing and having a socket 19 for receiving the ordinary operating handle such as is commonly used for raising and lowering jacks of this general character.

The gear 15 is axially fixed upon the vertical lifting screw 20, the lower end of which is journaled ..in the thrust bearing 21 formed in the The outer lifting member 22 is tubular in form, preferably square in cross section as shown, and is mounted, for vertical movement within the housing 10, being provided at its lower end with the, nut 23 normally receiving the unthreaded portion 24 of the screw 20,.when the jack is in the lowered or collapsed position, as shown'in Fig. 1. I v

The inner liftingmember 25 is also of tubular form, preferably square in cross section, and is slidable within the outer member 22, being prov'idedat its lower end with the nut portion'26 normally engaged by the screw 20 when the jack is in lowered position as shownin Fig. 1.

I A stud 27fis fixed in the lower end portion of the inner lifting member 25 and extends through the vertical slot 28 formed in one side of the outer lifting member 22, the upper end of said slot having the angular horizontally disposed portion 29. The stud 27 is also slidably received in the vertical groove 30 formed in the housing 10 in order to prevent axial movement of both of the lifting members during the time the inner lifting member is being raised to the limit of its movement relative to the outer lifting ,member.

The lower portion of the inner lifting member 25, just above the stud 27, is of reduced cross section, being preferably rounded as shown at 3 1-,in Fig. '7, forming the lugs 32 below said reduced portion and similar lugs 33 above thesame.

The upper portion of the outer lifting member 22 is provided with openings 34 adapted to receive the lugs 32 when the two :lif-ting .members are locked together in extended position, ,as will be later described, at which time the upper lugs 33 will rest .upon the flatupperendfifi of theputer lifting member.

The -outer liftingmember 22 is provided near its upper end with a pair .of ,studs 36 which are s lidably-received in the grooves 3, :formed in-ith'e housing, said grooves having the inclined ,anguliar portions 37a near their upperends terminatin in the vertical upper ends 37b. -fjhe ,studs 36 cooperating with these grooves axiallyturn the p l li n m e .22 om th po i on Shown in Fig. 2 to-that shown in ;Fig. 5, while the inner lifting member 25 is held against turning movement by the stud 2Z7 riding in the ,vertical groove 30 of the housing, the angular offset portion 29 of the groove 28 in the outer lifting member accommodating the lug 2:7 as ,the outer lifting ,member is turned to :the locked position.

the operation of the jack, assuming that the parts are in the normal, .or lowered -.pos i tion, ,as best ow-r n Fig 1, t ua o era n handle is connected to the socket l9 oustomary manner ,and rotated in .the proper direction," whereby through the pinion 16 and gear the screw 20 is rotated in a direction to raise the inner lifting member 25. The outer lifting member 22 at first remains stationary the nut 23 thereof is not engaged .by ,the screw. .A th nn r i t n memb i r is d to a point where the stud 2'7 thereon reaches the ,upper end .of the slot 28 in the outer lifting member, the Outer lifting member is pulled upward thereby until the nut 23 thereon is brought into engagement with the screw 20.

As the outer lifting member moves upward, the studs 36 thereon passing through the angular portions 37a of the grooves in the housing rotate said outer lifting member from the position shown in Fig. 2 to that shown in Fig. .6, the inner lifting member being held against axial mo rement by the stud 2'? engaged in the vertical groove 30 of the housing.

As the outer lifting member is rotated, the lugs 32 upon the inner lifting member will be engaged in he Openings 34 of h ou e l ting mem the stud 27 being receiyed in the angular offset p r en 29 of h 9i 2 a d the lu s 33 f the inner lifting member will engage over the flat upper end 35 of the outer lifting member.

As the rotation of the screw 10 continues, the nut 26 of the inner lifting member will pass upward out of engagement with the screw and the ,outer lifting member will continue to raise, earrying with. it the fully extending inner lifting member locked thereto as above described.

The squared opening 3,8 the upper end of -.axle or other portion of the vehicle, as in usual practice.

'In order to lower the jack, the screw is rotated in ,the'opposite direction, moving the outer lifting member downward until the studs 36 riding :back through the inclined portions 37a of the grooves in the housing rotate the same sufficiently to unlock the inner lifting member v therefrom, after which the nut upon the router lifting member will pass out of engagement with the lower end portionof the screw, while the ;nut .upon the inner lifting member will travel .down the screw until the parts assume the normal position as shown in Fig. l.

Lclaim: ,1. A lifting jack including a housing, a .screw within the housing, means for rotating the screw, a pair .of tubular lifting ,members nori mall-y telescoped within .the ho sing, nuts ,upon the lower portions of said lifting members for engagement with the screw, means upon the lower end of one of the lifting members for locking engagement with the upper portion @of 1-10 the other lifting member and means ;for axially turning .one of said lifting members at a predetermined position relative to the other lifting member and the housing to lock ,saidlifting members together.

- 2. A tin ia k includin a housing, a screw within the housin means for rotating the .screw, .a pair of tubular lifting members normally telescoped within the housing, nuts upon [the lower portions of said lifting members for enga fimentgwo with ,the screw, the upper portion of .one of the l t g m m ers h v penings therein, lugs upon the lower portion of the other lifting memher for locking engagement with ,said openings,

and means for axially turning one of said lifting.

members at a predetermined position relative .to the other lifting member and the housing .to lock said lifting members together.

3. A lifting ack including a housin a screw within the housing, means for rotating the screw; a pair of tubular lifting members normally telescoped within the housing, nuts upon the lower portions of said lifting members for engagement with the screw, means upon the lower end of one of the lifting members for locking engagement with the upper portion of the other lifting member, and means upon the housing and one of the lifting members for axially turning said last named lifting member to lock the lifting members together.

4. A lifting jack including a housing, a screw within the housing, means for rotating the screw, a pair of tubular lifting members normally telescoped within the housing, nuts upon the lower portions of said lifting members for engagement with the screw, the upper portion of one of the lifting members having openings therein, lugs upon the lower portion of the other lifting memb r for locking engagement with said openings,

and means upon the housing and one ofthe 1150 lifting members for axially turning said last named lifting member to lock the lifting members together.

- 5. A lifting jack including a housing, a screw within the housing, means for rotating the screw, a pair of tubular lifting members normally telescoped within the housing, nuts upon said lifting members for engagement with the screw, lugs upon the lower end of the inner lifting memher and apertures in the upper portion of the outer lifting member for locking engagement with said lugs, and coacting studs and inclined grooves in the outer lifting member and housing for automatically rotating the outer lifting member for locking the same to the inner lifting member when said inner lifting member has been raised to a predetermined point.

6. A lifting jack including a housing having inclined grooves therein, a screw within the housing, means for rotating the screw, 2. pair of tubular lifting members normally telescoped within the housing, nuts upon said lifting members for engagement with the screw, lugs at the lower end of the inner lifting member and openings at the upper end of the outer lifting member to receive said lugs, and studs upon said outer lifting member for engagement with the inclined grooves in the housing for automatically rotating the outer lifting member for locking the same to the inner lifting member when said inner lifting member has been raised to a predetermined point.

JOHN A. MORRISON. 

